First observations of avalanche-like behavior in p-GaN gate HEMTs with the buffer avalanche triggered layer

Abstract

A p-GaN gate high electron mobility transistor with the buffer avalanche triggered layer (BATL-HEMT) is experimentally demonstrated to exhibit repetitive avalanche-like behavior. One of the major limitations of conventional HEMTs is their limited avalanche capability, primarily due to the absence of an efficient removal path for the holes generated during avalanche breakdown. The local accumulation of these holes can indirectly induce severe thermal degradation, ultimately leading to potential device failure. However, in the proposed device, the unique P++P−−N++ structure initiates an avalanche effect within the buffer layer, thereby activating the established hole energy dissipation pathway. Under multiple repeated breakdown testing, the device can instantaneously dissipate high current densities without observable thermal degradation. Additionally, temperature-dependent breakdown measurements show that the BATL-HEMT exhibits a positive temperature coefficient characteristic of avalanche breakdown.